A question about leveling lumber

Discussion in 'Luthier's Corner' started by tjclem, Oct 10, 2011.


  1. tjclem

    tjclem Commercial User

    Jun 6, 2004
    Central Florida
    Owner and builder Clementbass
    I have a 1"thick piece of Spalted Maple I want to level and resaw. I used my joiner and got all 4 corners to sit level on the table saw then started feeding it through the planer to flatten the top. It seems the rollers in the planer are pressing down the piece so even though the whole face of the board is smooth it is still convex on that side. Sorry if for some of you this seems to be a basic question but I can't figure out how to level it. The boar has great color and figure to it. I don't want to toss it.
     

    Attached Files:

  2. Meatrus

    Meatrus

    Apr 5, 2009
    England
    Hand plane the high ends (thats if I understand whats going on correctly!).
     
  3. That's some stunning figure indeed!

    This is a bit hard for me, as I know the correct terms in Dutch, but do not know how these tools are called in English normally. But when you say _through_ a planer, I suppose you mean a thicknesser, because with a planer you feed the wood _over_ it (or is that what you call a jointer?).

    Anyways, the clue is you should first get one side of the wood flat before you thickness it. A thicknesser only takes care of even thickness, not making the board straight. If there's a curve in the wood, it will be either temporarly bent back or it is just fed in a curve through the thicknesser.

    So if you feed the wood _over_ a planer / jointer until the bottom of the wood is flat, you can then feed it through the thicknesser to make the top parallel with the bottom. (Feeding it over the planer doesn't put any stress on the wood, leaving it in its original shape and that way you can take out the curve at the bottom).

    I did the same with a neck blank that was curved and it worked well.
     
  4. TomKatCustom

    TomKatCustom

    Oct 21, 2010
    Here's what I'd do. I have a 16" thickness sander. I made a 15.5" x 27" sled out of 2 pieces of 3/4 mdf sammiched together so it's 1.5" inch thick. Screw the corners of the wood in question from the underside of the sled with 1.5" drywall screws, countersunk nicely so they bite into the piece and don't stick out of the bottom. Run this through the thickness sander until the surface is flat. I only take off 1/64th at a time so sometimes it takes a lot of passes. When the top is flat, I can flip it over and flatten the other side without the sled. This is how I prep my 8/4 solid body blanks.
     
  5. Stone Age

    Stone Age

    Apr 13, 2008
    Connecticut
    If you jointed one face so it sits flat without pressure, the planer should only be taking material from the highest point. It can't push the center lower than that. Set the planer so it barely touches the highest point, then take very light passes- 1/32 or so to check. It should start making a flat spot at the high point. It shouldn't be keeping the arc if the bottom is truly flat. It may snipe both ends, however.
     
  6. Reticle

    Reticle

    Jul 24, 2009
    Charleston SC
    One side should be jointed until it is 100% flat with the entire surface of it touching the infeed table of your thickness planer, not just on 4 corners.

    Btw, Awesome piece of wood!
     
  7. tjclem

    tjclem Commercial User

    Jun 6, 2004
    Central Florida
    Owner and builder Clementbass
    6" joiner 8.5" wide board this won't be pretty........ :scowl:
     
  8. tjclem

    tjclem Commercial User

    Jun 6, 2004
    Central Florida
    Owner and builder Clementbass
  9. pilotjones

    pilotjones

    Nov 8, 2001
    US-NY-NYC
    I've done boards that are too wide for the joiner, and very concave boards, but never both at once.

    Seems to me you've got to make repeated passes on the concave side, alternating putting each half of the board against the knives (with a 180* rotation between passes), until the concave side has become flat. You'll be shaving the leading and trailing ends only until you get there, and have to be sure not to press the the raised center into the knives prematurely. When I did my wide boards, I set the fence so that the center strip overlap was just half an inch.

    If your infeed or outfeed tables are not as long as the board, it will be very difficult to get rid of the concavity. Been there.
     
  10. I do not have a joiner at all, so I visited a local furniture builder and asked him to make the blank flat for me. Maybe that could be an option for you too?
     
  11. tjclem

    tjclem Commercial User

    Jun 6, 2004
    Central Florida
    Owner and builder Clementbass
    I guess this is what i will try next. Luckily I don't have that length problem. Thanks...t
     
  12. mikeyswood

    mikeyswood Inactive

    Jul 22, 2007
    Cincinnati OH
    Luthier of Michael Wayne Instruments
    I keep a 4' carrier board of 3/4" MDF around my planer for situations like these.
     
  13. tjclem

    tjclem Commercial User

    Jun 6, 2004
    Central Florida
    Owner and builder Clementbass
    Tried that
     
  14. tjclem

    tjclem Commercial User

    Jun 6, 2004
    Central Florida
    Owner and builder Clementbass
    Thanks all I ended up with a nice top
     
  15. Great! The way Pete suggested? Any pics to wrap up this thread nicely? :D
     
  16. tjclem

    tjclem Commercial User

    Jun 6, 2004
    Central Florida
    Owner and builder Clementbass
    Thanks Mr. Jones. Here is the top. It is gluing together now.
     

    Attached Files:

  17. pilotjones

    pilotjones

    Nov 8, 2001
    US-NY-NYC
    That looks nice, Tom. Glad it worked out.

    I'm interested to know how a carrier board is used.
     
  18. mikeyswood

    mikeyswood Inactive

    Jul 22, 2007
    Cincinnati OH
    Luthier of Michael Wayne Instruments
    I keep a side rail taped on that feeds the rollers and is consumed with each cut and I shim warped pieces where they will best be flattened.
     
  19. Wow that's a nice result indeed!!
     
  20. Primary

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